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Ultrasound picture of ovary: Injections of Lupron, Metrodin, Pergonal or Humegon allow the ovaries to develop many follicles as seen in this ultrasound immediately prior to egg retrieval. |
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Fertilized oocyte (2PN embryo): Immediately after fertilization, the egg contains two pronuclei. Each contains the chromosomal material from one of the genetic parents. |
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Four-cell embryo: Each of the cells is called a blastomere. The embryo is surrounded by a protein matrix "shell" called the zona pellucida. |
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Eight-cell embryo: On the third day after the egg retrieval, eight-cell embryos can be transferred to the uterus. On average, 10-15% of embryos such as this will implant after being transferred. |
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Hatched embryo: Prior to implantation, the embryo, now at the blastocyst stage, must hatch out of the zona pellucida. Only then can it attach to the mother's endometrial lining. |
